First remove xserver-xorg-input-synaptics and install xserver-xorg-input-libinput
After, add the following lines to /usr/share/X11/xorg.conf.d/40-libinput.conf
Section "InputClass"
Identifier "touchpad overrides"
Driver "libinput"
MatchIsTouchpad "on"
Option "Tapping" "on"
Option "TappingButtonMap" "lrm"
EndSection
And reboot now.-